On 09/09/2024 06:10, Gavin Shan wrote:

On 8/19/24 11:19 PM, Steven Price wrote:

quoted

From: Suzuki K Poulose <suzuki.poulose@arm.com>

The RMM (Realm Management Monitor) provides functionality that can be
accessed by a realm guest through SMC (Realm Services Interface) calls.

The SMC definitions are based on DEN0137[1] version 1.0-rel0-rc1.

[1]
https://developer.arm.com/-/cdn-downloads/permalink/PDF/Architectures/DEN0137_1.0-rel0-rc1_rmm-arch_external.pdf

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v4:
  * Update to match the latest RMM spec version 1.0-rel0-rc1.
  * Make use of the ARM_SMCCC_CALL_VAL macro.
  * Cast using (_UL macro) various values to unsigned long.
Changes since v3:
  * Drop invoke_rsi_fn_smc_with_res() function and call arm_smccc_smc()
    directly instead.
  * Rename header guard in rsi_smc.h to be consistent.
Changes since v2:
  * Rename rsi_get_version() to rsi_request_version()
  * Fix size/alignment of struct realm_config
---
  arch/arm64/include/asm/rsi_cmds.h | 136 +++++++++++++++++++++
  arch/arm64/include/asm/rsi_smc.h  | 189 ++++++++++++++++++++++++++++++
  2 files changed, 325 insertions(+)
  create mode 100644 arch/arm64/include/asm/rsi_cmds.h
  create mode 100644 arch/arm64/include/asm/rsi_smc.h

With the following minor comments addressed:

Reviewed-by: Gavin Shan <redacted>

Thanks for the review!

quoted

diff --git a/arch/arm64/include/asm/rsi_cmds.h

b/arch/arm64/include/asm/rsi_cmds.h
new file mode 100644
index 000000000000..968b03f4e703

--- /dev/null
+++ b/arch/arm64/include/asm/rsi_cmds.h

@@ -0,0 +1,136 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 ARM Ltd.
+ */
+
+#ifndef __ASM_RSI_CMDS_H
+#define __ASM_RSI_CMDS_H
+
+#include <linux/arm-smccc.h>
+
+#include <asm/rsi_smc.h>
+
+#define RSI_GRANULE_SHIFT        12
+#define RSI_GRANULE_SIZE        (_AC(1, UL) << RSI_GRANULE_SHIFT)
+
+enum ripas {
+    RSI_RIPAS_EMPTY = 0,
+    RSI_RIPAS_RAM = 1,
+    RSI_RIPAS_DESTROYED = 2,
+    RSI_RIPAS_IO = 3,
+};
+

The 'RSI_RIPAS_IO' corresponds to 'RIPAS_DEV' defined in
tf-rmm/lib/s2tt/include/ripas.h.
Shall we rename it to RSI_RIPAS_DEV so that the name is matched with
that defined in
tf-rmm?

Yes it should be renamed. This was posted based on the v1.0-rel0-rc1
spec and follows the naming there. But shortly after that spec was
released the decision to rename to RIPAS_DEV was made (as it's really
specifying that it's a device not that I/O is happening at an address).
I kept the naming to match the spec, but the next release of the spec
should have the RIPAS_DEV so I'll update to match that.

---> tf-rmm/lib/s2tt/include/ripas.h

/*
 * The RmmRipas enumeration represents realm IPA state.
 *
 * Map RmmRipas to RmiRipas to simplify code/decode operations.
 */
enum ripas {
        RIPAS_EMPTY = RMI_EMPTY,        /* Unused IPA for Realm */
        RIPAS_RAM = RMI_RAM,            /* IPA used for Code/Data by
Realm */
        RIPAS_DESTROYED = RMI_DESTROYED,/* IPA is inaccessible to the
Realm */
        RIPAS_DEV                       /* Address where memory of an
assigned
                                           Realm device is mapped */
};

quoted

+static inline unsigned long rsi_request_version(unsigned long req,
+                        unsigned long *out_lower,
+                        unsigned long *out_higher)
+{
+    struct arm_smccc_res res;
+
+    arm_smccc_smc(SMC_RSI_ABI_VERSION, req, 0, 0, 0, 0, 0, 0, &res);
+
+    if (out_lower)
+        *out_lower = res.a1;
+    if (out_higher)
+        *out_higher = res.a2;
+
+    return res.a0;
+}
+
+static inline unsigned long rsi_get_realm_config(struct realm_config
*cfg)
+{
+    struct arm_smccc_res res;
+
+    arm_smccc_smc(SMC_RSI_REALM_CONFIG, virt_to_phys(cfg),
+              0, 0, 0, 0, 0, 0, &res);
+    return res.a0;
+}
+
+static inline unsigned long rsi_set_addr_range_state(phys_addr_t start,
+                             phys_addr_t end,
+                             enum ripas state,
+                             unsigned long flags,
+                             phys_addr_t *top)
+{
+    struct arm_smccc_res res;
+
+    arm_smccc_smc(SMC_RSI_IPA_STATE_SET, start, end, state,
+              flags, 0, 0, 0, &res);
+
+    if (top)
+        *top = res.a1;
+
+    return res.a0;
+}
+
+/**
+ * rsi_attestation_token_init - Initialise the operation to retrieve an
+ * attestation token.
+ *
+ * @challenge:    The challenge data to be used in the attestation token
+ *        generation.
+ * @size:    Size of the challenge data in bytes.
+ *
+ * Initialises the attestation token generation and returns an upper
bound
+ * on the attestation token size that can be used to allocate an
adequate
+ * buffer. The caller is expected to subsequently call
+ * rsi_attestation_token_continue() to retrieve the attestation token
data on
+ * the same CPU.
+ *
+ * Returns:
+ *  On success, returns the upper limit of the attestation report size.
+ *  Otherwise, -EINVAL
+ */
+static inline unsigned long
+rsi_attestation_token_init(const u8 *challenge, unsigned long size)
+{
+    struct arm_smccc_1_2_regs regs = { 0 };
+
+    /* The challenge must be at least 32bytes and at most 64bytes */
+    if (!challenge || size < 32 || size > 64)
+        return -EINVAL;
+
+    regs.a0 = SMC_RSI_ATTESTATION_TOKEN_INIT;
+    memcpy(&regs.a1, challenge, size);
+    arm_smccc_1_2_smc(&regs, &regs);
+
+    if (regs.a0 == RSI_SUCCESS)
+        return regs.a1;
+
+    return -EINVAL;
+}
+

The type of the return value would be 'long' instead of 'unsigned long'
since
'-EINVAL' can be returned.

Good spot! The call site is casting back to long, so it "should work",
but clearly this is the wrong type.

quoted

+/**
+ * rsi_attestation_token_continue - Continue the operation to
retrieve an
+ * attestation token.
+ *
+ * @granule: {I}PA of the Granule to which the token will be written.
+ * @offset:  Offset within Granule to start of buffer in bytes.
+ * @size:    The size of the buffer.
+ * @len:     The number of bytes written to the buffer.
+ *
+ * Retrieves up to a RSI_GRANULE_SIZE worth of token data per call.
The caller
+ * is expected to call rsi_attestation_token_init() before calling this
+ * function to retrieve the attestation token.
+ *
+ * Return:
+ * * %RSI_SUCCESS     - Attestation token retrieved successfully.
+ * * %RSI_INCOMPLETE  - Token generation is not complete.
+ * * %RSI_ERROR_INPUT - A parameter was not valid.
+ * * %RSI_ERROR_STATE - Attestation not in progress.
+ */
+static inline int rsi_attestation_token_continue(phys_addr_t granule,
+                         unsigned long offset,
+                         unsigned long size,
+                         unsigned long *len)
+{
+    struct arm_smccc_res res;
+
+    arm_smccc_1_1_invoke(SMC_RSI_ATTESTATION_TOKEN_CONTINUE,
+                 granule, offset, size, 0, &res);
+
+    if (len)
+        *len = res.a1;
+    return res.a0;
+}
+
+#endif /* __ASM_RSI_CMDS_H */

diff --git a/arch/arm64/include/asm/rsi_smc.h

b/arch/arm64/include/asm/rsi_smc.h
new file mode 100644
index 000000000000..b76b03a8fea8

--- /dev/null
+++ b/arch/arm64/include/asm/rsi_smc.h

@@ -0,0 +1,189 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 ARM Ltd.
+ */
+
+#ifndef __ASM_RSI_SMC_H_
+#define __ASM_RSI_SMC_H_
+
+#include <linux/arm-smccc.h>
+
+/*
+ * This file describes the Realm Services Interface (RSI) Application

Binary
+ * Interface (ABI) for SMC calls made from within the Realm to the
RMM and
+ * serviced by the RMM.
+ */
+
+/*
+ * The major version number of the RSI implementation.  This is
increased when
+ * the binary format or semantics of the SMC calls change.
+ */
+#define RSI_ABI_VERSION_MAJOR        UL(1)
+
+/*
+ * The minor version number of the RSI implementation.  This is
increased when
+ * a bug is fixed, or a feature is added without breaking binary
compatibility.
+ */
+#define RSI_ABI_VERSION_MINOR        UL(0)
+
+#define RSI_ABI_VERSION            ((RSI_ABI_VERSION_MAJOR << 16) | \
+                     RSI_ABI_VERSION_MINOR)
+
+#define RSI_ABI_VERSION_GET_MAJOR(_version) ((_version) >> 16)
+#define RSI_ABI_VERSION_GET_MINOR(_version) ((_version) & 0xFFFF)
+
+#define RSI_SUCCESS        UL(0)
+#define RSI_ERROR_INPUT        UL(1)
+#define RSI_ERROR_STATE        UL(2)
+#define RSI_INCOMPLETE        UL(3)
+#define RSI_ERROR_UNKNOWN    UL(4)
+
+#define SMC_RSI_FID(n)       
ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,      \
+                           ARM_SMCCC_SMC_64,         \
+                           ARM_SMCCC_OWNER_STANDARD, \
+                           n)
+
+/*
+ * Returns RSI version.
+ *
+ * arg1 == Requested interface revision
+ * ret0 == Status /error
+ * ret1 == Lower implemented interface revision
+ * ret2 == Higher implemented interface revision
+ */
+#define SMC_RSI_ABI_VERSION    SMC_RSI_FID(0x190)
+
+/*
+ * Read feature register.
+ *
+ * arg1 == Feature register index
+ * ret0 == Status /error

              ^^^^^^^^^^^^^
              Status / error

Ack

quoted

+ * ret1 == Feature register value
+ */
+#define SMC_RSI_FEATURES            SMC_RSI_FID(0x191)
+
+/*
+ * Read measurement for the current Realm.
+ *
+ * arg1 == Index, which measurements slot to read
+ * ret0 == Status / error
+ * ret1 == Measurement value, bytes:  0 -  7
+ * ret2 == Measurement value, bytes:  7 - 15

                                         ^^^^^^
                                         8 - 15

quoted

+ * ret3 == Measurement value, bytes: 16 - 23
+ * ret4 == Measurement value, bytes: 24 - 31
+ * ret5 == Measurement value, bytes: 32 - 39
+ * ret6 == Measurement value, bytes: 40 - 47
+ * ret7 == Measurement value, bytes: 48 - 55
+ * ret8 == Measurement value, bytes: 56 - 63
+ */
+#define SMC_RSI_MEASUREMENT_READ        SMC_RSI_FID(0x192)
+
+/*
+ * Extend Realm Extensible Measurement (REM) value.
+ *
+ * arg1  == Index, which measurements slot to extend
+ * arg2  == Size of realm measurement in bytes, max 64 bytes
+ * arg3  == Measurement value, bytes:  0 -  7
+ * arg4  == Measurement value, bytes:  7 - 15

                                          ^^^^^^
                                          8 - 15

quoted

+ * arg5  == Measurement value, bytes: 16 - 23
+ * arg6  == Measurement value, bytes: 24 - 31
+ * arg7  == Measurement value, bytes: 32 - 39
+ * arg8  == Measurement value, bytes: 40 - 47
+ * arg9  == Measurement value, bytes: 48 - 55
+ * arg10 == Measurement value, bytes: 56 - 63
+ * ret0  == Status / error
+ */
+#define SMC_RSI_MEASUREMENT_EXTEND        SMC_RSI_FID(0x193)
+
+/*
+ * Initialize the operation to retrieve an attestation token.
+ *
+ * arg1 == Challenge value, bytes:  0 -  7
+ * arg2 == Challenge value, bytes:  7 - 15

                                       ^^^^^^
                                       8 - 15

One mistake and too much copy/pasting :(

quoted

+ * arg3 == Challenge value, bytes: 16 - 23
+ * arg4 == Challenge value, bytes: 24 - 31
+ * arg5 == Challenge value, bytes: 32 - 39
+ * arg6 == Challenge value, bytes: 40 - 47
+ * arg7 == Challenge value, bytes: 48 - 55
+ * arg8 == Challenge value, bytes: 56 - 63
+ * ret0 == Status / error
+ * ret1 == Upper bound of token size in bytes
+ */
+#define SMC_RSI_ATTESTATION_TOKEN_INIT        SMC_RSI_FID(0x194)
+
+/*
+ * Continue the operation to retrieve an attestation token.
+ *
+ * arg1 == The IPA of token buffer
+ * arg2 == Offset within the granule of the token buffer
+ * arg3 == Size of the granule buffer
+ * ret0 == Status / error
+ * ret1 == Length of token bytes copied to the granule buffer
+ */
+#define SMC_RSI_ATTESTATION_TOKEN_CONTINUE    SMC_RSI_FID(0x195)
+
+#ifndef __ASSEMBLY__
+
+struct realm_config {
+    union {
+        struct {
+            unsigned long ipa_bits; /* Width of IPA in bits */
+            unsigned long hash_algo; /* Hash algorithm */
+        };
+        u8 pad[0x200];
+    };
+    union {
+        u8 rpv[64]; /* Realm Personalization Value */
+        u8 pad2[0xe00];
+    };
+    /*
+     * The RMM requires the configuration structure to be aligned to
a 4k
+     * boundary, ensure this happens by aligning this structure.
+     */
+} __aligned(0x1000);
+
+#endif /* __ASSEMBLY__ */
+
+/*
+ * Read configuration for the current Realm.
+ *
+ * arg1 == struct realm_config addr
+ * ret0 == Status / error
+ */
+#define SMC_RSI_REALM_CONFIG            SMC_RSI_FID(0x196)
+
+/*
+ * Request RIPAS of a target IPA range to be changed to a specified
value.
+ *
+ * arg1 == Base IPA address of target region
+ * arg2 == Top of the region
+ * arg3 == RIPAS value
+ * arg4 == flags
+ * ret0 == Status / error
+ * ret1 == Top of modified IPA range
+ */
+#define SMC_RSI_IPA_STATE_SET            SMC_RSI_FID(0x197)
+
+#define RSI_NO_CHANGE_DESTROYED            UL(0)
+#define RSI_CHANGE_DESTROYED            UL(1)
+

According to the linked specification, the description for the third
return value
has been missed here.

ret2 == Whether the host accepted or rejected the request

Worse than just a documentation error - I'd completely forgotten to
check this extra return value in rsi_set_addr_range_state(). Thanks for
spotting this!

Steve

quoted

+/*
+ * Get RIPAS of a target IPA range.
+ *
+ * arg1 == Base IPA of target region
+ * arg2 == End of target IPA region
+ * ret0 == Status / error
+ * ret1 == Top of IPA region which has the reported RIPAS value
+ * ret2 == RIPAS value
+ */
+#define SMC_RSI_IPA_STATE_GET            SMC_RSI_FID(0x198)
+
+/*
+ * Make a Host call.
+ *
+ * arg1 == IPA of host call structure
+ * ret0 == Status / error
+ */
+#define SMC_RSI_HOST_CALL            SMC_RSI_FID(0x199)
+
+#endif /* __ASM_RSI_SMC_H_ */

Thanks,
Gavin